Stencil for sand blasting and method of making the same



Dee. 24, 1935.

R. H. KAVANAUGH STENCIL FOR SAND BLASTING AND METHOD OF MAKING THE SAME Filed Oct. 24, 1934 ilk/fl Patented Dec. 24, "1935 PATENT OFFICE .STENCIL FOR SAND BLASTING AND METHOD OF MAKING THE SAME Robert H. Kavanaugh, Brewer, Maine Application October 24, 1934, Serial No. 749,782

15 Claims. (Cl. 101-127) The chief object of the present invention is to provide an inexpensive stencil composed of a layer or strip of absorbent sheet material, such as cloth or paper, having openings cut therein collectively forming a design to be imparted to a surface on which the layer is placed, the layer being provided with a resiliently yielding protecting element resistant to a sand blast, and adapted to sufficiently cover the outer side of the layer and penetrate the same to enable a stencil embodying the invention to be repeatedly used.

Other objects will hereinafter appear.

Of the accompanying drawing forming apart of this specification,--

Figure 1 is a side view showing a portion of a stencil embodying the invention.

Figure 2 is an enlarged section on line 22 of Figure 1.

29 Figure 3 is a view similar to Figure 2 showing the margins of the openings cut in the layer protected by portions of the protecting elementto prevent' the fraying of the sheet material by the sand blast.

5 Figure 4 is a view similar to Figure 2 showing the outer side of the layer provided with a hard drying coating to stiffen the completed stencil, and the inner side provided with a filmof slow drying cementitious material and a backing layer of thin non-adhesive sheet material covering said film and separably secured to-the stencil thereby, for a purpose hereinafter described.

Figure 5 is a view similar to Figure 2, showing a final protective coating.

The same reference characters indicate the same parts in all of the figures.

My improved stencil is composed of a layer l2 of absorbent sheet material, which may be cloth or paper. The layer when made of cloth is preferably about twenty-five thousandths of an inch thick, although it may be considerably thinner. When the layer is of paper it may be about half or a quarter of the thickness of the cloth. I do not limit myself to any specified thickness.

The layer I2 is provided with openings l3 cut this product in the manufacture of stencils for sand blasting, particularly for border portions of designs. The rubber of commercial rubber tape penetrates the cloth thereof and so resiststhe abrading action of a sand blast that a stencil 5 made of rubber tape may be successfully used once.

I prefer, however, to use as the protecting element, the aqueous dispersion of rubber known as latex. This may be a preparation of rubber 10 latex containing a curing agent of well known character to give the desired qualities to the residue of rubber on drying. The preparation may consist of about forty per cent of rubber thinned down as desired, by water. 15

In either case the protecting element protects the outer side of the layer l2 and permeates the portion thereof between the outer and inner sides said element preferably protecting also the inner side. The protecting element is designated by I4 20 and indicated by stippling in Figures 2, 3 and 4.

To prevent the fraying of the sheet material whether the same be of cloth or paper, I may apply coatings M ofthe protecting element to the margin of the openings I3, as indicated by Fig- 25 ure 3.

The stencil may be stiffened if desired by a coating l6, (Figure 4), of hard drying material such as glue or varnish, said coating being hardened on the outer side of the layer. I2. 30

Figure 4 shows also a film I1 (indicated by heavy black lines) of slow drying glue or other slow drying cementitious material applied to the inner side of the layer I2, and a non-adhesive backing layer l8 preferably of thin tough paper-85 or thin cloth releasably secured to the stencil by said film. The separation of the backing layer from the stencil leaves a portion of the film l1 exposed in a tacky condition on the inner side of the stencil to temporarily secure the latter to the 40 surface on which it is placed, the object being to enable the impregnated layer ,IZ to be rolled or placed one layer upon another, and readily separated when required for use.

The preferred procedure is to first cut the 46 openings iii in the layer 12, and then apply the protecting element. The slow drying film l1 and the backing layer H! are preferably applied subsequently.

A stencil made in accordance with my invention is less expensive than one composed of a lace-like body anda protective coating applied thereto, as described by my Patent No. 1,954,672.

The layer I2 is preferably stiffened, as above stated, before the openings 13 are cut therein,

the stiffening agent 16 enabling the layer to be more easily handled during the cutting operation. The stiffening agent 16 may be a layer of shellac or of glue, or a mixture of latex and glue, or other stiffener. After the design openings are formed the layer may be provided with an additional or final protective coating 20, (Figure 5) of latex or of latex and glue, or other stiffening ingredient. If a latex and glue final coating mixture is used the preferred proportions are ninety per cent latex and ten per cent liquid glue by volume. Portions of the final coating may form the coating M on the margins of the openings. The layer l2, prepared as described, but without the design openings, may be sold as an article of manufacture, and subsequently completed by the formation of saidopenings by the user, who thus completes an operative stencil embodying the invention.

I claim:

1. A stencil composed of a layer of absorbent fibrous sheet material provided with a resiliently yielding protecting element resistant to a sand blast, and with openings collectively forming a design to be imparted by a sand blast to a surface on which the layer is placed, said protecting element occurring as a coating on the edges of said material defining such openings and thus serving to prevent fraying of said material.

2, A stencil composed of a layer of absorbent fibrous sheet material provided with openings collectively forming a design to be imparted to a surface on which the layer is placed, and provided also with a resiliently yielding protecting element resistant to a sand blast, said element protecting theouter side of the layer, permeating the portion thereof between its sides, and coating the edges thereof defining such openings to prevent fraying.

3. Astencil composed of a layer of absorbent fibrous sheet material provided with openings collectively forming a design to be imparted to a surface on which the layer is placed, and provided also with a resiliently yielding protecting element resistant to a sand blast, said element covering both sides of the layer permeating the intermediate portion thereof, and coating the edges thereof defining such openings to prevent fraying.

4. A stencil composed of a layer of absorbent fibrous sheet material provided with openings collectively forming a design to be imparted to a surface on which the layer is placed, and provided also with a resiliently yielding protecting element resistant to a sand blast, said element covering the outer side (i the layer and also the margins of the openings therein to prevent fraying.

5. A stencil composed of a layer of absorbent fibrous sheet material provided with openings collectively forming a design to be imparted to a surface on which the layer is placed, and providedalso with the dried residuum of an aqueous dispersion of rubber applied thereto in fluent condition and thereafter dried to constitute a protecting element covering the outer side of the layer and permeating the portion thereof between the sides.

6. A stencil composedof a layer of absorbent fibrous sheet material provided with openings collectively forming a;,design to be imparted to a surface on whichthe layer is placed, and provided also withthe dried residuum of an aqueous dis persion of rubber applied thereto in fluent condition and thereafter dried to constitute a protecting element covering both sides of the layer and permeating the portion thereof between the sides.

'7. A stencil composed of a layer of absorbent fibrous sheet material provided with openings collectively forming a design to be imparted to a surface on which the layer is placed, and provided also with the dried residuum of an aqueous dis- 5 persion of rubber constituting a protecting element covering the outer side of the layer and the margins of the openings therein.

8. A stencil composed of a layer of absorbent fibrous sheet material provided with openings 001- 10 lectively forming a design to be imparted to a surface on which the layer is placed, and provided also with the dried residuiun of an aqueous dispersion of rubber constituting a resiliently yielding protecting element resistant to a sand'blast, and with a stiffening coating of hard drying material hardened on the outer side of the layer.

9. A stencil comprising a layer of absorbent fibrous sheet material impregnated with the dried residuum of an aqueous dispersion of rubber con- 20 stituting a resiliently yielding protecting element resistant to a-sand blast, and provided with design-forming openings and with a final coating of sand blast resisting material comprising such residuum and protecting its outer side, portions 25 of said final coating protecting the margins of said openings. v

10. The method of making a stencil which consists in impregnating a layer of absorbent fibrous sheet material with an aqueous dispersion 30 of rubber affording when dried a resiliently yielding protecting element resistant to a sand blast, cutting design-forming openings in said layer and applying to the outer side of the layer a final protective coating of material comprising 35 also such aqueous dispersion of rubber, said final coating protecting the outer side of the layer and the margins of said openings.

11. The method of making a stencil which involves cutting design-forming openings in a layer 40 of absorbent fibrous sheet material and then impregnating said layer and coating the edges of said material defining said openings with an aqueous dispersion of rubber affording when dried a resiliently yielding protecting element resistant 45 to a sand blast.

12. A stencil comprising a layer of absorbent fibrous sheet material provided with openings collectively forming a design to be imparted to a surface on which the layer is placed, and pro- 50 vided also at least on its outer face with the dried residuum of an aqueous dispersion of rubber applied thereto in fluent condition and thereafter dried to afford a resiliently yielding protecting element resistant to a sand blast, and 55 with a film of slow drying cementitious material applied to its inner side, and a non-adhesive backing layer covering s'ai-d film and. releasably secured to the stencil thereby, the separation of said backing layer from the stencil leaving a 60 portion of said film exposed to temporarily secure the stencil to said surface. 7 p

13. As an article of manufacture, a layer of fibrous absorbent sheet material impregnated and coated at least onits vouter face with the dried 6 residuum of an aqueous dispersion of rubber applied thereto in fluent condition and thereafter dried to faiforda resiliently, yielding protecting element resistant to .a .sand blast, said sheet being 6; adapted to be converted into a stencil byqcuteh of an aqueous dispersion of rubber applied thereto in fluentcondition and thereafter dried to afford a resiliently yielding protecting element resistant to a sand blast, and provided with design-forming openings and with a final coating of sand blast resisting material protecting its outer side.

15. The method of making a stencil which comprises impregnating a layer of absorbent fibrous sheet material and coating at least its outer face with a fluent aqueous dispersion of rubber affording when dried a resiliently yielding protecting element resistant to a sand blast, cutting design-forming openings in said layer, and applying to the outer side of the layer a final protective coating of material resistant to a sand blast.

ROBERT H. KAVANAUGH. 

